add wait-on parameter preBuild

Author: bahmutov

netlify.toml

@@ -16,3 +16,4 @@ publish = "public"
   [plugins.inputs.preBuild]
     start = 'npm start'
     wait-on = 'http://localhost:5000'
+    wait-on-timeout = '3' # seconds

package-lock.json

@@ -18,7 +18,8 @@
   "dependencies": {
     "debug": "4.1.1",
     "ecstatic": "4.1.2",
-    "execa": "3.4.0"
+    "execa": "3.4.0",
+    "got": "9.6.0"
   },
   "repository": {
     "type": "git",

package.json

@@ -4,6 +4,7 @@ const http = require('http')
 const execa = require('execa')
 const debug = require('debug')('netlify-plugin-cypress')
 const debugVerbose = require('debug')('netlify-plugin-cypress:verbose')
+const { ping } = require('./utils')
 
 function serveFolder (folder, port) {
   const server = ecstatic({
@@ -12,6 +13,32 @@ function serveFolder (folder, port) {
   return http.createServer(server).listen(port)
 }
 
+async function waitOnMaybe (options = {}) {
+  const waitOnUrl = options['wait-on']
+  if (!waitOnUrl) {
+    debug('no wait-on defined')
+    return
+  }
+
+  const waitOnTimeout = options['wait-on-timeout'] || '60'
+
+  console.log(
+    'waiting on "%s" with timeout of %s seconds',
+    waitOnUrl,
+    waitOnTimeout
+  )
+
+  const waitTimeoutMs = parseFloat(waitOnTimeout) * 1000
+
+  try {
+    await ping(waitOnUrl, waitTimeoutMs)
+  } catch (err) {
+    debug('pinging %s for %d ms failed', waitOnUrl, waitTimeoutMs)
+    debug(err)
+    throw new Error(err.message)
+  }
+}
+
 async function runCypressTests (baseUrl, record, spec) {
   // we will use Cypress via its NPM module API
   // https://on.cypress.io/module-api
@@ -91,6 +118,16 @@ module.exports = function cypressPlugin (pluginConfig) {
   return {
     name: 'cypress netlify plugin',
     onInit,
+    preBuild: async (arg) => {
+      debug('cypress plugin preBuild inputs %o', arg.inputs)
+      const preBuildInputs = arg.inputs && arg.inputs.preBuild
+      if (!preBuildInputs) {
+        return
+      }
+
+      await waitOnMaybe(preBuildInputs)
+    },
+
     postBuild: async (arg) => {
       debugVerbose('postBuild arg %o', arg)
       debug('cypress plugin postBuild inputs %o', arg.inputs)

src/index.js

@@ -0,0 +1,34 @@
+// @ts-check
+const got = require('got')
+const debug = require('debug')('netlify-plugin-cypress')
+const debugVerbose = require('debug')('netlify-plugin-cypress:verbose')
+
+/**
+ * A small utility for checking when an URL responds, kind of
+ * a poor man's https://www.npmjs.com/package/wait-on
+ */
+const ping = (url, timeout) => {
+  debug('pinging "%s" for %d ms max', url, timeout)
+  const start = +new Date()
+  return got(url, {
+    retry: {
+      retries(retry, error) {
+        const now = +new Date()
+        debugVerbose(
+          `${now - start}ms ${error.method} ${error.host} ${
+            error.code
+          }`
+        )
+        if (now - start > timeout) {
+          console.error('%s timed out', url)
+          return 0
+        }
+        return 1000
+      }
+    }
+  })
+}
+
+module.exports = {
+  ping
+}